Seismic Insights into the March 2019 Earthquake Swarm near Goldfield, Nevada

The March 2019 earthquake swarm, designated S20190310.1, occurred approximately 50 km south-southwest of Goldfield in Esmeralda County, Nevada. This sequence began at 02:48 UTC on 10 March and concluded at 06:55 UTC on 11 March, encompassing 40 events over 28 hours and 7 minutes. Magnitudes ranged from -0.1 to 2.4, with most events registering below 1.0 and focal depths predominantly between 0 and 13 km. The swarm featured several notable shocks, including two magnitude 2.4 events on 10 March at 08:32 and on 11 March at 02:32, alongside clusters of smaller tremors concentrated in the early morning hours of 11 March.

This activity unfolded within the Basin and Range Province, a tectonically active region characterized by extensional faulting and normal faults that accommodate crustal stretching between the Sierra Nevada and the Colorado Plateau. Nevada experiences frequent seismicity due to its position in this province, where strain rates average 10-20 nanostrain per year. The specific locale lies near the transition to the Walker Lane belt, a northwest-trending zone of right-lateral shear that accommodates a portion of the Pacific-North American plate boundary motion. Historical mining districts around Goldfield, active since the early 1900s, have documented minor seismic events linked to both natural faulting and anthropogenic influences, though the 2019 swarm aligns with natural patterns observed in the area.

Swarm sequences like this one are common in the region and typically reflect fluid migration or aseismic slip along fault networks rather than mainshock-aftershock sequences driven by a single large rupture. Prior swarms since 2000 include single events in 2004, 2005, 2010, 2015, and 2016, indicating episodic low-level activity without escalation to damaging earthquakes. Depths in the 2019 sequence, mostly shallow at 0-5 km for larger events, suggest involvement of near-surface faults common in Basin and Range grabens.

No damage or felt reports were associated with these microearthquakes, consistent with their low magnitudes. Ongoing monitoring by regional networks helps track such swarms, contributing to improved understanding of strain accumulation in this portion of the western United States.

References

• USGS Earthquake Catalog (earthquake.usgs.gov)
• Nevada Seismological Laboratory historical records
• Basin and Range Province tectonic summaries from the Geological Society of America